LG RT-21FA35RX, RT-21FA35V, RT-21FA35VX, RT-21FA315EX, RT-21FA315PX Service Manual

COLOR TV

SERVICE MANUAL

CAUTION

BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

CHASSIS : MC-049B

MODEL:RT-21FA35R/RX/V/VX

MODEL:RT-21FA315EX/PX

website:http://biz.LGservice.com

e-mail:http://www.LGEservice.com/techsup.html

- 2 -

CONTENTS

Contents...................................................................................................................2

Safety Precautions..............................................................................................3

Control Descriptions..........................................................................................4

Specifications........................................................................................................7

Adjustment Instructions .................................................................................8

Trouble Shooting.................................................................................................12

Printed circuit board.........................................................................................16

Block Diagram ......................................................................................................19

Exploded View....................................................................................................20

Exploded View Parts List ..............................................................................21

Replacement Parts List .................................................................................22

SVC. Sheet..................................................................................................................

- 3 -

SAFETY PRECAUTIONS

Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in
the Schematic Diagram and Replacement Parts List.
It is essential that these special safety parts should be replaced with the same components as recommended in this manual to
prevent X-RADIATION, Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.

General Guidance

An isolation Transformer should always be used during
the servicing of a receiver whose chassis is not isolated from
the AC power line. Use a transformer of adequate power rating
as this protects the technician from accidents resulting in
personal injury from electrical shocks.

It will also protect the receiver and it's components from being
damaged by accidental shorts of the circuitry that may be
inadvertently introduced during the service operation.

If any fuse (or Fusible Resistor) in this TV receiver is blown,
replace it with the specified.

When replacing a high wattage resistor (Oxide Metal Film
Resistor, over 1W), keep the resistor 10mm away from PCB.

Keep wires away from high voltage or high temperature parts.

Due to high vacuum and large surface area of picture tube,
extreme care should be used in handling the Picture Tube.
Do not lift the Picture tube by it's Neck.

X-RAY Radiation

Warning:

To determine the presence of high voltage, use an accurate
high impedance HV meter.

Adjust brightness, color, contrast controls to minimum.
Measure the high voltage.
The meter reading should indicate

23.5

¡ 1.5KV: 14-19 inch, 26 ¡ 1.5KV: 19-21 inch,

29.0 ¡ 1.5KV: 25-29 inch, 30.0 ¡ 1.5KV: 32 inch
If the meter indication is out of tolerance, immediate service
and correction is required to prevent the possibility of
premature component failure.

Before returning the receiver to the customer,

always perform an AC leakage current check on the exposed
metallic parts of the cabinet, such as antennas, terminals, etc.,
to be sure the set is safe to operate without damage of
electrical shock.

Leakage Current Cold Check(Antenna Cold Check)

With the instrument AC plug removed from AC source,
connect an electrical jumper across the two AC plug prongs.
Place the AC switch in the on position, connect one lead of
ohm-meter to the AC plug prongs tied together and touch other
ohm-meter lead in turn to each exposed metallic parts such as
antenna terminals, phone jacks, etc.
If the exposed metallic part has a return path to the chassis, the
measured resistance should be between 1MΩ and 5.2MΩ.
When the exposed metal has no return path to the chassis the
reading must be infinite.
An other abnormality exists that must be corrected before the
receiver is returned to the customer.

Leakage Current Hot Check (See below Figure)

Plug the AC cord directly into the AC outlet.

Do not use a line Isolation Transformer during this check.

Connect 1.5K/10watt resistor in parallel with a 0.15uF capacitor
between a known good earth ground (Water Pipe, Conduit, etc.)
and the exposed metallic parts.
Measure the AC voltage across the resistor using AC
voltmeter with 1000 ohms/volt or more sensitivity.
Reverse plug the AC cord into the AC outlet and repeat AC
voltage measurements for each exposed metallic part. Any
voltage measured must not exceed 0.75 volt RMS which is
corresponds to 0.5mA.
In case any measurement is out of the limits specified, there is
possibility of shock hazard and the set must be checked and
repaired before it is returned to the customer.

Leakage Current Hot Check circuit

The source of X-RAY RADIATION in this TV receiver is the
High Voltage Section and the Picture Tube.
For continued X-RAY RADIATION protection, the
replacement tube must be the same type tube as specified in
the Replacement Parts List.

1.5 Kohm/10W

To Instrument's
exposed 
METALLIC PARTS

Good Earth Ground
such as WATER PIPE,
CONDUIT etc.

AC Volt-meter

IMPORTANT SAFETY NOTICE

0.15uF

- 4 -

DESCRIPTION OF CONTROLS

All the functions can be controlled with the remote control handset.
Some functions can also be adjusted with the buttons on the front
panel of the set.

Remote control handset

Before you use the remote control handset, please install the bat­teries. See the next page.

1. POWER

switches the set on from standby or off to standby.

2. NUMBER BUTTONS

switches the set on from standby or directly select a number.

3. MENU

selects a menu.

4. EYE/*(option)

switches the eye function on or off.

5.

D/ E

(Programme Up/Down)

selects a programme or a menu item.
switches the set on from standby.
scans programmes automatically.

F / G

(Volume Up/Down)

adjusts the volume.
adjusts menu settings.

OK

accepts your selection or displays the current mode.

6. Q.VIEW

returns to the previously viewed programme.

7. TELETEXT BUTTONS (option)

These buttons are used for teletext.
For further details, see the ÔTeletextÕ section.

8. PSM (Picture Status Memory)

recalls your preferred picture setting.

9. FAVOURITE

selects a favorite programme.

10. TURBO PICTURE / SOUND BUTTON (option)

selects Turbo picture and sound.

11. MUTE

switches the sound on or off.

12. TV/AV

selects TV or AV mode.
switches the set on from standby.

(Without TELETEXT / With PIP)

OK

PR

VOL

PR

VOL

PLAY

P/STILL STOP

REC

REW

FF

I/II SSM LIST

PSM

PIP

FAVOURITE

Q.VIEW

SLEEP

SWAP

INPUT

SIZE

9/4PIP

STILL

POSITION

0

TV/AV

MENU

PICTURE

SOUND

1

2 3

4

5 6

7

8 9

POWER

MUTE

EYE/

PR

PR

T U R B O

( )

( )

1

2

10

5

18

13

15

11

12

3

14

6

4

16

9

8

19

(With TELETEXT / PIP)

PSM

PIP

FAVOURITE

Q.VIEW

SLEEP

?

MIX

TIME

SWAP

INPUT

REVEAL MODE

SIZE

STILL

POSITION

9/4PIP

i

M

EYE/

PR

PR

TEXT/

7

- 5 -

13. I/II/*(option)

selects the language during dual language broadcast. (option)
selects the sound output.

14. LIST

displays the programme table.

15. SLEEP

sets the sleep timer.

16. SSM/

*

(option) (Sound Status Memory)

recalls your preferred sound setting.

17. SURROUND (

ºº

/

*

) (option)

selects surround sound.

18. VCR BUTTONS

control a LG video cassette recorder.

19. PIP BUTTONS (option)
PIP

switches the sub picture on or off.

PR +/-

selects a programme for the sub picture.

SWAP

alternates between main and sub picture.

INPUT

selects the input mode for the sub picture.

SIZE

adjusts the sub picture size.

STILL

freezes motion of the sub picture.

POSITION

relocates the sub picture in clockwise direction.

9/4 PIP

switches on or off the 9 or 4 sub pictures.

*

: No function

COLOURED BUTTONS : These buttons are used for teletext (only

TELETEXT models) or programme edit.

(Without TELETEXT / PIP)

POWER MUTE

123

456

789

MENU/INDEX

TV/AV

0

EYE/

Q.VIEW

LIST

I / II /

( )

PR

( )

PR

OK

VOLVOL

PSM SSM/ SLEEP

PICTURE SOUND

/

TURBO/

FAVOURITE

TV

1

2

3

4

5

6

8

10

11

12

13

14

15

17

16

9

TEXT/MIX/ SIZE/ HOLD/

Q.VIEW

LIST

UPDATE/

PSM SSM/ SLEEP/ M

X

TIME/ REVEAL/

?

PICTURE SOUND

/

TURBO/

FAVOURITE

7

(With TELETEXT / Without PIP)

- 6 -

Front panel

RF/RT-21FA35 series

ON/OFF

MENU OK VOL PR

2

L/MONO

1

3 4

5

6

7

2

1. MAIN POWER (ON/OFF)

switches the set on or off.

2. POWER/STANDBY INDICATOR

illuminates brightly when the set is in
standby mode.
dims when the set is switched on.
blinks when signal is input from the remote
control.

3. REMOTE CONTROL SENSOR

4. MENU

selects a menu.

5. OK

accepts your selection or displays the cur­rent mode.

FF / GG

(Volume Up/Down)

adjusts the volume.
adjusts menu settings.

DD / EE

(Programme Up/Down)

selects a programme or a menu item.
switches the set on from standby.

6. AUDIO/VIDEO IN SOCKETS (AV2)
(option)

Connect the audio/video out sockets of
external equipment to these sockets.

7. HEADPHONE SOCKET (option)

Connect the headphone plug to this sock­et.

8. EYE (option)

adjusts picture according to the surround­ing conditions.

Note :

a. Do not place any heavy objects (over 4Kg) on

the RF/RT-21FA35 series models.

b. Shown is a simplified representation of

front or side panel. Here shown may be
somewhat different from your set.

ON/OFF

MENUOKVOL

PR

RF/RT-21FB25 series

1

2

3

4 85

ON/OFF

MENU

OK

VOL PR

VIDEO

AUDIO

L

R

AV

RF/RT-15/21FB55 series

2 3 4 75

1

8

RF/RT-17/21FB75 series

1

2 3 4 5

RF/RT-21FC45 series

1

24 5 3 8

VIDEO

L/MONO

RAUDIO

AV2

7

6

VIDEO RL AUDIO

AV2

7

6

VIDEO

L

R

AUDIO

AV2

7

6

6

RF/RT-15/21FB95 series

1

2 3 4 85

RF/RT-21FB35 series

ON/OFF

MENU OK

VOL PR

VIDEO AUDIO

AV

VIDEO AUDIO

L/MONO

R

AV3

1 2 3 4 7 765 6

- 7 -

SPECIFICATIONS

Note : Specification and others are subject to change without notice for improvement.

F Scope

This specification can be applied to all the television related to
MC-049B Chassis.

F Test and Inspection Method

1) Capacity : Follow LG electronics TV testing Standard.

2) Another Required Standard

- EMI : Following CE Standard (EN55020, EN55013)

- Safety : Following CB Standard (EN55013)

F Requirement for Test

Testing for standard of each par must be followed in below
condition

1) Temperature : 20

± 5¡C

(CST must be tested 40

± 5¡C . Humidity : 50%)

2) Relative Humidity : 65

± 10%

3) Power : Standard input Voltage (110-240V~, 50/60Hz)

4) Measurement must be performed after heat-run more than
20min.

5) Adjusting Standard for this chassis is followed a special
standard.

No

1

2

3

4

5

6

7

8

Item

Receiving System

Receiving Channel

Input Voltage

Market

Screen Size

Tuning System

Operating Environment

Storage Environment

Remark

For EU/ For Non EU

For EU/ For Non EU

NTSC-M (Multi - model)

Non EU

EU

FLAT / CONVENTIONAL

200 PR. (OPTION)

Specification

1) PAL/SECAM BG

2) PAL/SECAM DK

3) PAL I/I

4) NTSC M

5) SECAM-L/LÕ

6) NTSC 4.43(AV)

1) VHF : E2 ~ E12

UHF : E21 ~ E69

CATV : S1 ~ S20

HYPER : S21 ~ S41

2) L/LÕ : B,C,D

3) VHF : 02 ~ 13

UHF : 14~ 69

CATV : 02 ~ 71

110-240V~, 50/60Hz

240V~, 50Hz

EU,CIS, China, Asia, Africa

14Ó ~ 21Ó

FVS 100Program

1) Temp. : 0 ~ 45 deg

2) Humidity: 85% under

1) Temp. : -20 ~ 60 deg

2) Humidity: 85% under

F General Specification

1. Application Object

These instructions are applied to all of the color TV, MC-049B.

2. Notes

(1) Because this is not a hot chassis, it is not necessary to use

an isolation transformer. However, the use of isolation
transformer will help protect test instrument.

(2) Adjustment must be done in the correct order.But the

adjustment can be changed by consideration of mass
production.

(3) The adjustment must be performed in the circumstance of

25±5¡C of temperature and 65±10% of relative humidity if
there is no specific designation.

(4) The input AC voltage of the receiver must keep rating

voltage in adjusting.

(5) The receiver must be operated for about 15 minutes prior

to the adjustment.

3. Focus adjustment

3.1. Preliminary steps

Tune the TV set to receive a digital pattern.
(SVC mode:Automatically mode change the STANDARD
MODE)

3.2. Adjustment Method

1) Single Focus CPT

Adjust the upper Focus volume of FBT for the best focus of
horizontal line A,vertical line B.

4. Purity & Convergence adjustment

4.1. Color purity adjustment

(1) It makes CPT enough to demagnetization.
(2) Receive the signal of red raster.
(3) Loosen fixed screw of DY and closely to CPT funnel part.
(4) Check the center of screen that PURITY MAGNET of CPT

by crossing adjustment. At this time, 4 & 6 pole magnet is
located to magnet of nothing.

(5) Move the DY to make equal red on whole screen and it

does not to make the DY by fixed screw after check a
simple color of Red/Green/Blue and white raster whether or
not it is a pollution of color.
(At this time, take care raster of screen and DY must fixing
in the condition which maintains a horizontality.)

(6) Check the receiver by move direction. When adjustment is

not working, adjust with the assisted MAGNET.

4.2. Convergence adjustment

These adjustments can the best condition of focus after
finished purity adjustment.

(1) Receive the signal of CROSS HATCH that BACK RASTER

is black.
(2) Adjust brightness and luminosity till dot appear 9 ~12.
(3) Open angle of the two tab of 4 pole MAGNET by isogonic

angle and accord with vertical line of red and blue color in

the middle of screen.

- 8 -

ADJUSTMENT INSTRUCTIONS

A

B

<Fig 1. PAL Digital Pattern(EU05CH)>

Assembling DY to

CPT

CPT Assembling

As preparatory operations before
assembling CPT, wind cotton Tape for
protecting to CPT NECK and DY, CPT
connection parts. At this moment, end
of tape should be over-lapped and
wound in direct route to the NECK.

Let the screen Standard condition.
Operate Heat-Run at least 15
minutes.

Torque is to be 9-11 kg f.cm when
fixing DY.

Fix the Magnet to the position as
shown picture below. Be careful not to
make CPT neck shadow while
adjusting DY.

HEAT RUN

Degaussing

STC Adjustment

PURITY Adjustment

DY Fixing

SCREEN Voltage adj.

W/B Fixing

FOCUS not yet ADJ.

STC not yet ADJ.

DYC not yet ADJ.

Convergence Magnet

15 ~ 20mm

¢‚

¢‚

6Pole

4

2

(4) Maintain as angle of (3) and rotate the tab to accord with

vertical line of Red and Blue color in the middle of screen.

(5) Open angle of the two tab of 6 pole magnet by isogonic

angle and accord with vertical line of Red/Blue and Green.

(6) Maintain as angle of (5) and rotate the tab to accord with

horizontal line. In case of twisted horizontal line,repeat
adjustment of (3) ~ (5) remembering the movement of
Red/Green/Blue color.

(7) Move the DY to best condition of convergence and attach

the CPT to a rubber-chock for fixed DY.

5. Screen voltage adjustment

(1) Receive the PAL or SECAM(NTSC) signal into RF mode

regardless of channel.

(2) If you press the ÒADJÓbutton in LINE SVC mode(IN-START

button),the LINE SVC mode changes to screen adjustment
mode.

(3) Adjust the screen volume of FBT jack,When width line is

seen turn the FBT screen volume at the position of
disappearance it.

(4) Press the TV/AV button to exit SVC mode.

6. White balance adjustment

NOTE : When adjusting white balance automatically,connect the

adjustment JIG in SVC mode.(When pressing ,MUTE
button on remote control, it changes to CPU OFF MODE
and screen displays ÒAUTOÓ.)

(1) Receive 100% white pattern.
(2) Adjust LOW Light status(4.5FL) of CUT R,CUT B at CG:60.
(3) Adjust HIGH LIght status(35FL) of WDR R,WDR B at

WDR G:450.

(4) Repeat above step (2) and (3) for the best condition each

status of High Light and Low Light.

* Auto adjustment

<CAUTION> W/B Program ÒTwbeng_v049Ó

- W/B adjustment after Cutoff

: Instart -> adj. -> mute(cutoff)-> tv/av(wb)
Release key is EXIT key

- W/B adjustment

: Instart -> mute(cpuoff)
Release key is TV/AV key

7.Deflection setting Data Adjustment

7.1 Adjustment preparation

(1) Tune the TV set to receive an Digital pattern(EU05CH).
(2) Deflection setting data adjustment is operate by SVC

communicator.
(3) Enter the deflection adjustment mode by selection

SERVICE1 on SERVICE MENU after pressing LINE SVC

MODE(IN-START KEY).
(4) Use the CH

D ,E key to select adjustment item.

(5) Use the VOL

F ,G key to increase/decrease data.

<Note>

(1) When adjusting a deflection, adjust N50Hz of PAL signal

first and adjust a deflection at Normal 60Hz(NTSC).
(2) Adjust a deflection as shown below.

PAL 4:3 -> NTSC 4:3
(3) After finishing deflection adjustment, press the ENTER key

to exit in adjustment mode.

* Before adjusting the PIP P(PIP Position), store the

deflection data in the EEPROM by using the ÒENTERÓ key.

7.2 Adjustment

(1) VL(Vertical Linearity) adjustment:

Adjust the top & bottom size of inner circle to be equal.
(2) VA (Vertical Amplitude) adjustment:

Adjust so that the circle of a digital circle pattern should be

located interval of 6~7mm from the effective screen of the

CPT.
(3) SC (S correction) adjustment:

Adjust so that all distance between each lattice width of

top/center/bottom are to be the same.

* Setting the CPT Default(Initial data) value like that, because
it is decide by CPT DY value

2. White balance IIC Parameter

Program

Sub Add

Start Bit

Stop Bit

Offset

Polarity

EP_Rom_S

R_Amp

TWBeng_v049

1C8

12

4

0

1

9091

R_Cut

TWBeng_v049

1C3

12

4

0

1

8A8B

B_Amp

TWBeng_v049

1CA

12

4

0

1

9495

- 9 -

Menu

X

Y

Color Temperature

288

295

9000¡K

266

273

13000¡K

EU

N-EU

<Table 1> White Balance Color analyzer

Menu

CUT R

CUT G

CUT B

WDR R

WDR G

WDR B

LOW LIGHT

HIGH LIGHT

0 ~ 511

0 ~ 511

0 ~ 511

0 ~ 511

0 ~ 511

0 ~ 511

60

60

60

450

450

450

Range

DATA

<Table 2> White Balance Initial Data

<Table 3> White Balance Initial Data

1. IC

VCD IC

EP_ROM

VCT49xyi

24C16

Micronas

ST, ATMEL

0 A 0

Name

Maker Algorithm

Program

Vcd Slave

TWBeng_v049

BCF0

Program

Eprom_Slave

TWBeng_v049AESpeed1Delay

30

B_Cut

TWBeng_v049

1C5

12

4

0

1

8E8F

Speed/ Plus 1 1 1 1

Menu